Actually, these are collectible and could possibly be worth a lot. The Genesis is more collectible and more popular with gamers than the Master System. Depending on which version of the Genesis and Master System you have and what games you have and the completeness/condition of everything you could get as little as $20 for each system with games or well over $100.
The Genesis had 3 official regular versions that were released during it's life: Genesis 1, Genesis 2, and Genesis 3. Each of the 3 models were released at different times when the Genesis was a competitor for the NES and SNES and had different attributes and capabilities that make each one worth different amounts of money today.
The Genesis 1 was the original, was the largest with the most ports on the back, and had more features than the ones that came after it. It is not rare but the version that says "High Definition Graphics" on the top of it is rarest and is the best one to have since it was made with better electronics on the inside that gives it superior video and audio from later variations of the model 1 or any model 2 and 3. The more common and later revision model 1 Genesis lacks the "High Definition Graphics" logo and the better video and audio output.
The Genesis model 2 is about as common or even more so as the Genesis 1 but was more bare bones. It had no headphone jack/volume control, less ports on the back, and was smaller and lighter than the model 1. However, it is compatible with the 32X and the Sega CD(either version) like the model 1 is.
The model 3 which was released at the end of the run of the Genesis is the rarest version. It will sell for the most in general but because of it's limited fanbase it can be had for less than a model 1 or 2 Genesis at times as the demand and price fluctuates wildly. It was compatible with Japanese Genesis(Mega Drive) games. Other than that It is a no frills console. It's compatible with NO other add ons that were released for the Genesis(32X, Sega CD, Game Genie, Power Base Converter) because it has no expansion port. Also, like the Genesis 2 it has no headphone jack/volume control and is so small and light it is about the same size and weight as a Genesis controller.
There are others released more recently like the Firecore that featured built in games that are official Sega products and another like the Sega CDX in the 90's that was combo Genesis/Sega CD but these are not considered regular Genesis consoles and you didn't say you had anything out of the ordinary. The CDX is quite valuable though at about $100 or higher; the Firecore was relatively rare so it has a decent value at about $30 to $50.
The Master System 1(the first version) sells for more if you have more peripherals with it(2 controllers, phaser light gun, etc). It was the most common version of the Sega Master System. In general, average/common games are actually worth a little more on the Master System than the Genesis because of them being rarer.
The Master System II sells for more but the price fluctuates a bit because it is much rarer then the 1st version but also has less fanbase. It could sell for up to $50 or more for the console alone if it's complete and in great shape. With 8 average games I'd say it'll bump the value up another $20 or so.
The value of any games depend on their scarcity and condition/completeness. Some games can be worth over $100 but this is not common. Most are worth about $5 to $10. If sold in a lot with a console you'd have to give a bundle price since some games are so worthless and unpopular that you'd never be able to sell them by themselves. The best thing to do is go on Ebay and see what they have sold for under completed listings and not what people are just asking for them to see what kind of value each game has. You may have 1 or 2 that are worth selling separately from the rest because they are worth a good amount of money. If you have the manual and box they are considered complete or CIB(complete in box). This will only add to their value. The same goes for the consoles. If you saved the box and/or manual for the Genesis and/or Master System then it will be more desirable to any collectors.
Minimum values are here with 8 average/common games:
Genesis 1 with 8 games: $30-$40, High Definition Graphics version with 8 games: $35-$45
Genesis 2 with 8 games: $30-$40
Genesis 3 with 8 games: $15-$50
Master System 1 with 8 games: $30-$40
Master System II with 8 games: $45-$55